Galactic magnetic fields, from radio polarimetry of the WIM

Abstract

Multi-frequency radio polarimetry of the diffuse Galactic synchrotron background gives new viewpoints on the Galactic magnetic field. Rotation measure maps reveal magnetic structures on arcminute to degree scales, such as a ring in polarization that we interpret as a magnetic tunnel. A complication using this technique is depolarization across the beam and along the line of sight. The influence of beam depolarization has been estimated using numerical models of the magneto-ionic ISM, through which polarized radiation propagates. The models show that depolarization canals similar to those observed can be caused by beam depolarization, and that the one-dimensional gradients in RM needed to produce these canals are ubiquitous in the medium.

4 pages, 3 figures, to appear in the proceedings of "How does the Galaxy work? A Galactic Tertulia with Don Cox and Ron Reynolds", eds Alfaro, Perez & Franco

References in corpus (4)

• Multi-frequency polarimetry of the Galactic radio background around 350 MHz: I. A region in Auriga around l = 161, b = 16
• Characteristics of the structure in the Galactic polarized radio background at 350 MHz
• Multi-frequency polarimetry of the Galactic radio background around 350 MHz: II. A region in Horologium around l = 137, b = 7
• A Highly Ordered Faraday-Rotation Structure in the Interstellar Medium